The exemplary embodiments relate to a multi-projection display that displays images projected by a plurality of projector units on a large screen, and projector units used for the same.
FIG. 15 is a schematic diagram of a multi-projection display 900. The multi-projection display 900 includes a plurality of projector units PJA, PJB, PJC, and PJD disposed horizontally or vertically, as shown in FIG. 15. The multi-projection display 900 displays one large image on a screen SCR such that unit images IA, IB, IC, and ID projected by the projector units PJA, PJB, PJC, and PJD are tiling-projected. Since the multi-projection display 900 can display higher-definition and higher-intensity images than common projectors, it will come into widespread use in the field of business such as theaters, art museums, museums, rooms sized for seminars or meetings, mini theaters, public offices, companies, and for personal or recreational use, such as in home theaters.
Such a multi-projection display has a problem in that variations in intensity and tone of color from projector unit to projector unit prevent a totally even image from being displayed. FIG. 16 is a schematic to explain the problems of this multi-projection display.
Specifically, in this multi-projection display, even if projection images having equal pixel values in the whole projection region (for example, white display images with the highest intensity in the whole projection region) are projected from the projector units, with variations in intensity from one projection unit to another, the relative brightness on the screen SCR varies by, for example, 100%, 95%, 90%, and 95%, as shown in FIG. 16.
Also, in this multi-projection display, when the tone of color varies from one projection unit to another, for example, when the image projected by one projector unit is reddish, the region to which the projection image from the projector unit is projected also becomes reddish.
Thus, the multi-projection display has a problem in that variations in intensity and tone of color from one projector unit to another prevent a totally even image from being displayed.
FIG. 17 is a schematic of the function of a related-art multi-projection display in which the foregoing problems are solved. A related-art multi-projection display (not shown) controls light amounts in such a way that it projects images having an equal pixel value in all projection regions (for example, white display images with the highest intensity in all projection regions, red display images with the highest intensity in all projection regions, green display images with the highest intensity in all projection regions, or blue display images with the highest intensity in all projection regions) as adjusting unit images by the projector units. The related art multi-projection display further photographs the images with a digital camera or measures the color with a colorimeter to calculate adjustment amount from one projector unit to another. The related art multi-projection display also controls original-image information to be inputted to electrooptic modulators from one projector unit to another using the calculated adjustment amount (see, for example, paragraphs 42 and 43 of JP-A-2001-251651).
Accordingly, with the related-art multi-projection display, for example, when the projector units project projection images having an equal pixel value in all projection regions (for example, white display images with the highest intensity in all projection regions), even with variations in intensity from one projection unit to another, the intensities of the projector units can be consistent with one another by adjusting the brightness on the screen SCR to an even brightness, as shown in FIG. 17.
Also, in the related art multi-projection display, even with variations in tone of color from one projection unit to another, for example, when the projection image formed in one projector unit is reddish, the tone of color of the projector units can be consistent with one another by decreasing the red component of the image information to be sent to the projection unit.
Thus, the related-art multi-projection display allows the intensity and tone of color of the projector units to be consistent with one another, providing totally even images.
However, to have consistency in intensity and tone of color of the projector units, the related art multi-projection display must adjust the light quantity by reducing the light transmittance of the electrooptic modulators of at least the projector units, other than a projector unit having the lowest intensity, as shown in FIG. 17. This requires the use of gradation sources in the electrooptic modulators, posing the problem of decreasing the number of effective gray levels inherent to the related-art multi-projection display or narrowing the dynamic range.